In order to succeed, people need a sense of self-efficacy, to struggle together with resilience to meet the inevitable obstacles and inequities of life.
People's beliefs about their abilities have a profound effect on those abilities. Ability is not a fixed property; there is huge variablitiy in how you perform.
Fortunately, most human behavior is learned observationally through modeling from others.
Most of the images of reality on which we base our actions are really based on vicarious experience.
People who believe they have the power to exercise some measure of control over their lives are healthier, more effective and more successful than those who lack faith in their ability to effect changes in their lives.
Given appropriate social conditions, decent, ordinary people can be led to do extraordinarily cruel things.
Learning would be exceedingly laborious, not to mention hazardous, if people had to rely solely on the effects of their own actions to inform them what to do.
Moral justification is a powerful disengagement mechanism. Destructive conduct is made personally and socially acceptable by portraying it in the service of moral ends. This is why most appeals against violent means usually fall on deaf ears.